Pay station telephone system



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Filed Dec. 20, 1941.

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Patented Sept. 5, 1944 UNITED STATE s PATENT OFFICE PAY STATION'Il'liEPHONE` SYSTEM York Application December 20, 1941, lSerial No.423,758 e'oiaims. (C1. 17e-6.31)

This invention relates to telephone systems and more particularly tosystems in which calls from `lines equipped with coin boxes are chargedagainst the calling person through the collection of deposited coins ortokens.

In dial switching telephone systems, to enable a calling person at 'thesubstation of a line equipped with a coin box to establish calls, it hasbeen the customary practice to instruct him to deposit a coin and if thecall is one to be .terminated outside of the local calling area, thatis, an area requiring a, toll charge, to then dial zero to secure theassistance of an A operator. In response to the extension of aconnection to a trunk terminating at the ,A switchboard, an operator atthat switchboard answers the call by plugging one of her cord circuitsinto the trunk jack, causes the coin box apparatus atthe callingsubstation to refund the initially deposited coin and then requestsinformation from the calling person concerning the desired connection.The operator then makes out a tollticket and requests the callingpersonto deposit coins in payment for the initial period of conversationas determined by the tariff rate for a call to the desired destination.The operator after audibly hearing'the deposit of the required coinsthen proceeds to establish the desired connection by dialing or keyingup the digits of the desired line number or through the assistance of arecording toll operator. When the called subscriber responds, if theconnection is successfully established, the operator notes the time theconversation starts on the toll ticket and times the duration of theconversation. Just prior to the expiration of the initial period, theoperator challenges the calling person and informs him that if he wishesto continue the conversation he should signal her when Vhe is through.When the operator receives such a termination signal she informs thecalling person as to the additional coins which are required for theovertime period of conversation and listens for their deposit. When theconversation is terminated, all deposited coins are collected if thecall was successful, or returned if not successful. From the foregoingbrief description it will be apparent that on every toll call theoperator is required to make out a toll ticket for timing the call andmust give the call supervision throughout its duration. Also, some ofthe operators time is consumed in the establishment of the connection. Y

It is the object of the present invention to pro- -vide facilities forhandling toll calls at coin box stations whereby persons using suchstations may establish short haul toll connections by dialing andwhereby the services of an operator to supervise such connections forthe purpose of collecting and refunding deposited coins are reduced to aminimum and fewer operators are therefore required to handle such -tolltramo.

In accordance with the present invention this object is obtainedbydirecting all short haul, low tariff calls from coin box lines, suchas ten and -iifteen cent calls, to a trunk outgoing to a tandem office,such trunks yhaving separate appearances in the banks of district oroffice selectors and separate lamp and jack appearances at the Aoperators switchboard foreach tariff rate. On

i theinitiation of a call from a'coin box -line the calling person rstdeposits a coin to enable the call to be started -and yafter receivingthe usual dial tone proceeds to dial the directory number of the Wantedline. The office code and numerical digits of the line number thusVdialedare registered in the sender of the calling oflice and inaccordance with the oice code digits registered, a district and, ifrequired, an oiiice selector are set to select an idle trunk extendingto a tandem office. The oice code will determine over which one of itsdistrict selectorv or office selector appearances the tandem trunk willbe seized, thatis, the appearance which is allocated to the propertariff rate for the desired connection.

Y thefA operator then plugs one of her cord circuits into the jackassociated with the v'lighted lamp, whereupon the coin initiallydeposited is refunded and the lighted charge rate lamp is extinguished.The operator then -requests` the calling person to deposit coins in theamount indicated by the charge rate lamp which was lighted and afterhearing the deposit of such coins, disconnects her cord circuit from thejack. When she disconnects her cord circuit from the jack the tandemsender is signaled to proceedy to control the completionv of theconnection to the wanted line in accordance with the digit informationregistered therein.

When the called subscriber answers, the tming of the call -is Vinitiatedand after 41/2 minutes the deposited coins areY collected. After fiveminutes the proper charge rate lamp Ais ashed to Vindicate to theoperatorV that an overtime inter- Val has been reached. Theoperatoragain rplugs acord circuit into the jack associated with the-flashing lamp and directs the calling personto signal her when he isthroughV talking. In most cases the subscriber will elect to terminatethe Aconversation at once. If hedoesnot elect to do so, however, theoperator leaves the plug of the cord circuit in the trunk jack, writes aticket and handles the call in the manner hereinbefore described. It isthus apparent that unless the conversation extends beyond the initialperiod the services of the A operator are required but for a very briefinterval and that upon a call in which the conversation extends beyondthe initial period, which calls will constitute only about ten per centof the short haul toll trac from coin box lines, the continuedsupervision of the operator will be required only during the overtimeperiod during which the conversation is continued.

For a clearer understanding of the invention, reference may be had tothe following detailed description taken in connection with theaccompanying drawings, in which:

Fig. 1 shows in the upper portion thereof a coin box line terminating ina panel type oflice, a line finder, district selector, office selectorand sender of which are schematically illustrated; shows in the lowerportion thereof a coin box line terminating in an oflice of thewell-known crossbar type, the line switch, district and oftlce selectorframes, sender link switch frame, sender and marker of which areindicated by suitably labeled boxes; and shows in the right portionthereof the selector switch appearances of the outgoing end of a trunkextending from the originating oice to a tandem oflice;

E. B. Mead. The interrupters are arranged to be clutched to the shaft ofthe driving motor by the operation of clutch magnet 504. Interrupters505 to 5|I, inclusive, are miscellaneous powerdriven interrupters on theinterrupter frame of the originating oilice.

It will be assumed that a person at the substation |00 of the coin boxline which terminates Figs. 2, 4 and 5 taken together show the outdgoing end of a tandem trunk;

Fig. 3 shows in the upper portion thereof the tandem oice end of thetandem trunk terminating in a, tandem district selector and in the lowerportion thereof such portions of a tandem sender associable with thetrunk as are necessary to an understanding of the invention; and

Fig. 6 is a chart showing how the several figures of the drawings shouldbe arranged to completely disclose the invention.

Referring to the drawings, the apparatus of the originating panel typeoffice X, disclosed schematically in the upper portion of Fig. 1, may beof the well-known type such as is disclosed, for example, in Patent No.1,862,549, granted June 14, 1932, to R. Raymond and W. J. Scully,

and the apparatus of the originating crossbar';1

type office Y, disclosed schematically in the lower portion of Fig. 1,may be'of the well-known type such as is disclosed for example in PatentNo. 2,093,117, granted September 14, 1937, to W. W. Carpenter. Theinteroice tandem trunk may be n used in common by a panel and a crossbaroffice if they are in the same building, by strapping both the (i0) and(c) cross connections but if such offices are not in the same building,it is to be understood that a separate group of tandem trunks wouldextend from each office to the tandem office, and that a trunk whenoutgoing from the panel office would be connected by the crossconnections (p) to selector bank appearances in such office and whenoutgoing from the crossbar oice would be connected by the crossconnections (c) to crossbar switch appearances in such office. rlheapparatus of the tandem ofee disclosed schematically in Fig. 3 may be ofthe general type disclosed in Patent No. 1,840,132, granted January 5,1932, to T. H. Roberts, the tandem sender, however, being slightlymodified las will be presently described. The interrupters 502 and 503of Fig. 5 form a part of a motor-driven charge timer 550 of the generaltype disclosed in Patent No. 2,112,375, granted March 29, 1938, to

in the panel type ofce X, desiring a toll connection deposits a nickelin the nickel coin slot of the coin box apparatus |0|, and upon removingthe substation receiver from the switchhook, becomes connected by a linefinder |02, over the line finder-district selector trunk |03 and theusual sender link circuit (not shown) with an idle sender |04 in themanner fully described in the Patent No. 1,862,549 hereinbefore referredto. When the calling line becomes connected with the sender the usualdial tone is transmitted from the sender to apprise the calling personthat he may proceed to dial the digits of the desired line number. Itwill further be assumed that a number is dialed, the office code digitsof which indicatethat a ten cent charge is required for the initialperiod of conversation. In accordance with the present invention, alltoll calls to be terminated in the nearby toll area, such as callsinvolving ten and fifteen cent initial charges, are routed over specialtandem trunks to a tandem office through which they are then completed.Therefore, in response to the registration of the oflice code digitsindicative of the fact that the call is to be extended into a ten centzone of the exchange area, the sender |04 proceeds to control thesetting of the district selector |05 and the office selector |06 toselect an idle trunk extending to the tandem oiiice. It will be assumedthat the trunk disclosed in Figs. 2 to 5, inclusive,

is idle and is therefore seized by the oflice selector |06 over the bankterminal set |01.

It will be noted that this trunk has two terminal bank appearances inthe bank of office selector |06, one of which, |01, is allocated forseizure on all toll calls for which the initial charge rate is ten centsand the other of which, |08, is allocated for seizure on all toll callsfor which the initial charge rate is fifteen cents. It will be obviousthat if it should be desired to enable connections to be established bydial control from coin box lines to subscribers lines terminating inmore remote offices of the exchange area, other appearances of thetandem trunk in banks of selector switches could be provided, allocated,for example, to calls for which the initial charge rate might be twentycents, twenty-five cents, etc.

When the tandem trunk is seized ground is applied over the sleeve brush|00 and sleeve terminal ||0 of the trunk and thence to the sleeveterminal of all other bank appearances of the trunk and multiplesthereof to mark the trunk as busy. When all dialed digits have beenregistered in the sender |04, a circuit is established from batterythrough the right winding of relay 300 and over contacts of cam 30| inthe incoming end of the tandem trunk ofthe tandem office, over trunkconductor 302, the No. 8 back contact of relay 200, the No. 5 backcontact of relay 20|, through the upper winding of polarized relay 202,the No. 7 back contact of relay 203, the No. 8 back contact of relay204, conductor 205, through the upper winding of relayY I I, the No. 6back contact of relay ||2, over the tip bank terminal of terminal set|01, tip brushes of selectors |06 and |05, contacts of cam ||3 at thedistrict selector |05, thence through the windings of relays traced tothe originating sender.

in the sender |04, returning over contacts of cam H4, ring brushes ofselectors and |05, ring bank terminal of terminal set I01, the N0. 2back contact of relay H2, conductor 206, the No. 2 back contact of relay204, the No. 1 back contact of relay 203, through the lower winding ofpolarized relay 202, the No. 3 back contact of relay 20|, the No. 2 backcontact of relay 200, trunk conductor 303, contacts of cam 304 to groundthrough the left winding of relay 300. Relays IjI and 300 operate inthis circuit, relay 300 functioning to cause the association of a tandemsender with the incoming end of the tandem trunk and relay III uponoperating establishing a locking circuit for itself extending frombattery through the winding of relay II5, through the lower winding andcontacts of relay III, conductor H6, the No, 5 normal contacts of relay203, conductor H1, sleeve terminal H0, brush I09 to ground in the oiceselector.

Relay I I5 operates in this locking circuit, locks over its upper frontcontact to ground on conductor H6, connects the trunk conductors 205 and206 over its middle upper and lower contacts to the tip and ringterminalsA of the terminal set |01 independently of the contacts ofrelay H2, and establishes a circuit for relay l I2 which may be tracedfrom battery through its Winding, over the inner front contacts of relayH5 to ground. Relay H2 upon operating at its back contacts `disconnectsthe multiples of all unused appearances of the trunk. These operationstake place while the circuits at the tandem oilice are recognizing theclosure, advancing the trunk and link circuits and selecting an idlesender.

Upon the seizure of the tandem sender, a pulse receiving circuit isestablished between the originating sender |04 and the tandem sender,schematically disclosed in the lower portion of Fig. 3, which extends aspreviously traced from the sender |04 to trunk conductor 302, thenceover contacts of cam 305, back contact of relay 306, upper normalcontacts of relay 301', upper back contact of relay 308, seriallythrough the windings of impulse responsive relays 309, 3I0

-and 3I I, lower back contact of relay 308, inner the end ofl the lastcode impulse transmitted for the units digit series, with relay 3I4operated,

relay 308 operates in a circuit from battery through its winding, overthe upper contact of relay 3I4, the lower back contact of relay 3I5,

the back contact of relay 309 to ground. With relay 308 operated theimpulse receiving circuit is prepared for the reception of the finalpositive impulse transmitted from the sender |04 which circuit extendsas previously traced over the upper normal contacts of relay 301, thenceover the upper front contact of relay 308, through vthe winding of thenegatively polarized impulse responsive relay 309, over the inner lowerfront contact of relay 308 and thence as previously Relay 308 at Iitsupper back contact removes the shunt from resistance 3I6 and bridgesthis resistance across the impulse receiving circuit in parallel withthe winding of relay 309. The winding of relay 309 is now :connectedreversely -into the impulse receiving circuit whereby it is responsivelto the receipt of the inal heavy positive impulse and establishes acircuit from ground over its front contact, over the upper normalcontacts of relay 3l 5, through the winding of relay 3I5 and resistance3I1 to battery. Relay 3I1 upon operating locks over its inner upperalternate contacts to ground and prepares a circuit for relay 3I8. Uponthe termination of the nal heavy positive impulse when relay 309releases, relay 3I8 energizes in a circuit from battery throughresistance 3I9, the winding of relay 3 I8, the inner upper alternatecontacts of relay 3| 5 to ground. With relays 3 I 5 and 3I8 now bothoperated a circuit is established for transfer relay 301 extending frombattery through its Winding over the lower front contact of relay 30B,the inner upper front contact of relay 3|4, the upper contacts of relays3|5 and 3I8 to ground. With relay 301 operated, the circuit previouslyestablished by the operation of relay 3M for relay 320 is opened at thelower back contact of relay 301, relay 301 is locked over its lowerfront contact to ground at the lower front contact of relay 3 I4, andthe circuit extending back to the originating sender is transferred fromthe winding of relay 300 to the windings of relays 32| and 322, trunkconductor 302 being now extended over the contacts of cam 305, the backcontact of relay 306, the upper alternate contacts of relay 301, overthe lower normal contacts of relay 320 to battery through the winding ofrelay 32| and trunk conductor 3103 being now extended over contacts ofcam 3I3, the back contact of relay 3I2, the inner lower alternatecontacts of relay 301, theupper normal contacts of relay 320, to groundthrough the winding of relay 322,.

At the outgoing end of the tandem trunk polarized relay 202 operated itsarmature against its left contact in response to the nal heavy positiveimpulse, in turn causing the operation of relay 201 in a circuitrfrcmbattery through its winding and the left contact of relay 202, conductor208 to ground at the No. 3 contact of relay H2. -Relay 201 uponoperating locks in a circuit from battery through its winding over itsupper contact and over the No. 1 back contact of relay 200 to ground onconductor 20B. Atthe end of the heavy positive impulse, polarized relay202 operates its armature Vagainst its right contact thereby opening theoperating circuit of relay 201 and with relay 201 locked operated,establishes a circuit from battery through the winding of relay 203,over the inner lower iront contact of relay 201 andthe right contact ofrelay 202 `to ground on conductor 208. Relay 201 also connects groundover the No. 2 back contact of relay 203 and its lower front contact topeg count register conductor 209 and at its back contact opens the timedrelease circuit. Relay 203 upon operating locks over its No. 4 contactsto ground on conductor 208; opens the peg count register circuit at itsNo. 2 back contact; at its No. 5 alternate contactsl establishes a newholding circuit for relay H5 extending from conductor H5 Vand conductor:l I1 to the sleeve terminals of the trunk in oiiice selectors of thepanel oice; vconnects ground over its No. 3 contacts and conductor I I8to sleeve terminals in the ofiice switches of the crossbar oilice incases where the trunk is allocated to a crossbar oice; at its Nos. 1 and7 back contacts opens the circuit previously traced through the windingsof polarized relay 202; extends trunk conductor 205 over the No. 8 backcontact of relay 204, the No. '1 front contact of relay 203, the No. 6back Contact of relay 204 t ground through the lower winding of relay2|3 and extends trunk conductor 206 over the No. 2 back contact of relay204, the No. 1 front contact of relay 203, and the No. l back contact ofrelay 204 to battery through the upper winding of relay 2|3. Relay 20|upon operating disconnects the windings of polarized relay 202 from thetrunk conductors 302 and 303 at its Nos. 3 and back contacts, bridges atits No. 6 contacts the contacts of relay 500 included in its operatingcircuit; at its No. 5 front Contact connects ground over the No. 8 backcontact of relay 200 and thence over the circuit traced to batterythrough the winding of relay 32| at the tandem sender, thereby causingthe operation of relay 32| followed by the operation of relay 323, andconnects ground over its No. 4 contacts, conductor 2 I 4, the No. 4 backContact of relay 40|, conductor 402, to the armature of interrupter 501which upon making its left Contact completes the circuit of relay 5I2over conductor 5|3, the No. 3 back contact of relay 200, conductor 2 I 5to battery through the winding of relay 5|2, Relay 5I2 operates in thiscircuit to start a timing cycle to be later described.

The operation of relay 323 at the tandem sender signals the sender thattiming thereat must be suspended since there will be some delay beforethe A operator answers and checks the deposit of the required coins inthecoin box of the callingline. Relay 323 closes a circuit from groundover its upper front contact and the upper back contact of relay 324 tobattery through the winding of relay 325. Relay 325 upon operatingcauses the operation of relay 326 over an obvious circuit, relay 326upon operating, locking under the control of relay 321 over its lowerfront contact and the back contact of relay 321 and closingr an obviouscircuit for relay 323. With relay 328 operated or unoperated, ground isconnected over its'contacts, the lower normal contacts of relay 329 andthe back contact of relay 325 to the back contact of timing relay 330 tostart the operation of timing relays 330 to 335 to time out the tandemsender but since relay 325 has been operated this timing start circuitis not effective and the timing out of the sender is therefore delayed.

When the originating sender has completed the transmission of the nalheavy positive impulse, it advances the sequence switch of the districtselector |05 into the trunk closure position and the originating senderthen becomes disconnected from the line nder-district trunk |03 and isrestored to normal. Relay 2|3 now operates in a circuit which may betraced from battery through its upper winding, the No. 1 back contact ofrelay 204, the No, 1 front con# tact of relay 203, the No. 2 backcontact of relay 204, conductor 206, the middle lower front contact ofrelay II5, ring terminals and brushes of selectors |06 and |05, contactsof cams ||4 and I I9, ring brush of the line finder |02, thence over thecalling line loop over the tip brush of line nder |02, contacts of cams|20 and ||3,

tip brushes and terminals of selectors |05 and |00, middle upper frontcontact of relay ||5, conductor 205, the No. 8 back contact of relay204, the No. '1 front Contact of relay 203, the No. 6 back contact ofrelay 204 to ground through the winding of relay 2|3. Relay 2|3 uponoperating over this circuit establishes a circuit from ground over itslower contacts, conductor 2|6, the No. 5 back contact of relay 400 tobattery through the winding of slow-to-release relay 403 and at itsupper contacts, prepares the circuit of relay 2|1. Relay 403 uponoperating locks in a circuit extending from battery through its windingover the No. 5 back contact of relay 400, the upper front contact ofrelay 403, the No. 5 normal contacts of relay 40|, conductor 404, toground at the No. '7 back contact of relay 204 and at its inner upperfront Contact connects ground to conductor 405 and through the windingof relay 40| to battery. Relay 40| now operates, locking over its No. 5alternate contacts and conductor 404 to ground at the No. 1 back contactof relay 204; opens at its No. 5 normal contacts the locking circuit forrelay 403 just traced; completes the circuit of relay 2|1 which may betraced from battery through its winding over the upper contacts of relay2|3, conductor 2|8, the No. 2 back contact of relay 406, No. l frontcontact of relay 40| to ground at the back contact of relay 401; opensat its No. 4 back contact the previously traced circuit for relay 5|2which thereupon releases and at its No. 2 contacts connects the sleeveof answering jacks 2|9 and 220 over the No. 1 contacts of relay 20|,conductor 22|, No. 2 contacts of relay 40| to ground through the windingof relay 401. The circuit to the sleeves of the jacks is not closeduntil this time in order to prevent the operator from interfering withthe call should she inadvertently connect to the trunk.

Relay 2|1 upon operating with relay ||5 operated to indicate a ten centtoll call, establishes a circuit for the lamp 224 which may be tracedfrom battery over the contacts of'relay 2 |1, conductor 222, lowercontacts of relay I |5, conductor 223, through lamp 224 to groundthereby lighting the lamp which is adjacent to jack 2|9 as a signal tothe A operator that a call has been established over the trunk to whichthe lamp and jack appertain requiring a tollcharge of ten cents. Had thecalling person dialed a called line number for which a toll charge offifteen cents was required, the oice selector |06 would have been set toseize the trunk over the terminal set |08 thereby causing the operationof relays |2| and |25 in the same manner as relays III and I5 wereoperated. The circuits would then have functioned in the mannerpreviously described except that upon the operation of relay 2|1'acircuit would have been established from battery over its contacts,conductor 222, the lower contacts of relay |25, conductor 225, to groundthrough the lamp 226, associated with jack 220 thereby lighting suchlamp to indicate that the call has been established requiring a tollcharge of fifteen cents. In order that the operator may more readilydetermine the amount of charge required the lamps 224 and 226 may havedistinctive caps, the cap of lamp 224, for example, being red for theten cent rate and the cap of lamp 226 being green for the fteen centrate.

Y Initial response of an operator VInresponse to the lighted lamp 224,an operator at the A switchboard inserts the answering plug of an idlecord circuit, such as the cord circuit schematically illustrated at 221,into the jack 219 associated with the lamp 224, whereupon the circuit ofrelay 401 previously traced iscompleted. Relay 401 upon operating, atits inner upper contact establishes the circuit of relay 408 whichoperates, and opens at its back Contact the previously traced circuit ofrelay 211 which now releases and extinguishes the lam'p 224. Relay 228is also operated upon the connection of a cord circuit to the jack 219in a circuit which may be `traced in part over the tips of the cord plugand jack 219, the No. 7 back contact of relay 229, the winding of relay228, the No. 2 back contact of relay 229 and the rings of jack 219 andthe cord plug. Relay 408 upon operating connects a source of tonecurrent associated with conductor 409 over its No. 8 contacts, conductorvv1110, the No. '1 back contact of relay 229, tips of jack 219 and cordplug to the operators cord circuit to warn the operator against startingconversation with the calling person until the connection between thecalling line and the operators position has been cut through; connectsthe winding of relay 401 over its No. 1 contacts and conductor 411directly to the sleeve of jack 219 and establishes a circuit for relay412 which may be traced from battery through its winding, over conductor413, the No. 6 back contact of relay 229, contacts of relay 228,conductor 414 to ground over its No. 6 contacts.

Relay 412 now operates, locks in a circuit extending from batterythrough its Winding, over conductor 413, the No. 6 back contact of relay229, conductor '415, its No. 4 contacts to ground over the No. 6contacts of relay 408; at its No. 2 back contact removes ground fromconductor 416 extending to the line discharge network comprisingresistances 230, 231 and condenser 232; at its No. 3 contacts connectsresistances 514 and 515 across the calling line in bridge of thewindings of relay 213 in a circuit which may be traced from batterythrough the upper winding of relay 213, the No. 1 back contact of relay204, the No. 3 back contact of relay 229, conductor 233, the No. 6 backcontact of relay 411, the No. 2 back contact of relay 418, the No. 3contacts kof relay 412, conductor 419, serially through resistances 514and 515, conductor 420, the No. 6 back contact of relay 204 to groundthrough the lower winding of relay 213, and connects ground over its No.5 contacts and conductor 421 to the Xed contact of interrupter 505. Assoon thereafter as the interrupter cam causes the closure of itscontacts, a circuit is completed from ground connected to conductor 421,thence over conductor 422, over the inner lower normal contacts andthrough the winding of counting relay 423 and resistance 425 to batteryand through the winding of counting relay 424 and resistance 426 tobattery. Relay 423 now operates but the winding of relay 424 beingshunted over its own No. 7 back contact does not operate so long as thecontacts of interrupter 505 are closed. Relay 423 upon operating locksover its inner lower alternate contacts to ground over the No. 5contacts of relay 412. Upon the 'next opening of the contacts ofinterrupter 505 the initial operating circuit of relay 423 is opened andrelay 424 now operates in a circuit from battery through resistance 426,through its winding, over the inner lower alternate contacts of relay423 to ground over the No. 5 contacts of relay 412. With relay 424 nowoperated, a shunt is established from conductor 419 over the No. 1contacts of relay 424, and conductor 432 around resistance 515 therebyreducing the shunt across the calling line to a value of 50 ohms. Withrelays 423 and 424 both operated, the circuit oi relay 500 isestablished from battery through its winding over conductor 516, the No.3 contacts of relay 424, the lower contacts of relay 423 to ground atthe No. 2 back contact of relay 411. lRelay 500 upon operating shuntsresistance 514 over its upper contacts thereby reducing the resistanceof the shunt across the calling line to zero.

Upon the next closure of the contacts associated with interrupter cam505 ground is connected from conductor 421 over such contacts, conductor422, the No. '1 front contact of relay 424`to a point between thewinding of relay 423 and resistance 425, whereupon the winding of relay423 becomesshunted and relay 423 releases. The circuit of relay 500 isnow opened at the lower contacts of relay 423 and relay 500 releases.With relay 423 releasedy and relay 424 still operated, a circuit isestablished from battery through the Winding of relay 204, overconductor 234, the inner upper back contact of relay 423, the No. 6contacts of relay 424 to ground applied to conductor 421 over the lowercontacts of relay 401. Relay 204 upon operating locks over its No. 5contacts -to ground applied to conductor 421 over the lower contacts ofrelay 401; disconnects the windings of relay 213 from the calling lineat its Nos. 1 and 6 back contacts while the line is stillshort-circuited; establishes a holding circuit for relay 403 extendingfrom battery through its winding, over the No. 5 back contact of relay400, the No. 3 contacts of relay 401, conductor 428 to ground at the No.7 front contact of relay 204; transfers the tip and ring trunkconductors 205 and 201i` at its Nos. 2 and 8 contacts from contacts ofrelay 203 to contacts of relay 229 in preparation for the return of theinitially deposited coin at the coin box 101 of the calling line andestablishes the operating circuit for counting relay 41.8 which may betraced from battery through resistance 429, the winding and the No.5normal contacts of relay 418, the upper back contact of relay 423,conductor 235, the No. 3 contacts of relay 204,Y conductor 236, the No.4contacts of relay 424 to ground at the No. 2 front contact of relay 412.The operating circuit for counting relay 411 is also prepared at thistime from ground, thence as traced over the No. 5 normal contacts ofrelay 418 through the winding of relay 411 and resistance 430 to batterybut the winding of relay 411 is shunted at this time over its own No. 7back contact so long as relay 424 remains operated and relay 411 doesnot therefore operate. Relay 418 upon operating now locks over ,acircuit from battery through resistance 429, its winding and No. 5alternate contacts, conductor 235 and thence to ground as traced.

Return of initially deposited coin With relay 418 operated coin returnbattery is connected from the source 511, over the No. 9 back contact ofrelay 518, conductor 519, lower contacts of relay 403, No. 1 backcontact of relay 406, No.V 1 back contact of relay 411, No. 4 contactsof relay 418, conductor 431, over the Nos. 1 and 8 back contacts ofrelay 229 and the Nos. 2 and 8 front contacts of relay 204, thence astraced over the tip and ring conductors of the established connectionthrough the magnet of coin box 101 to ground over contacts closedthereat by the deposited coin. The coin box magnet is now energized insuch a manner as to deposit the coin in the return chute where it may berecovered by the calling person. Upon the second opening of the contactsassociated with interrupter cam 505, the holding circuit for countingrelay 424 extending from ground on conductor 42|, over the contacts ofinterrupter 505, conductor 422, the inner lower normal contacts of relay423, through the Winding of relay 424 and resistance 426 to battery isopened and relay 424 releases. With relay 424 released, the shunt of thewinding of relay 4|1 is removed and relay 4|1 operates over a circuitfrom battery through resistance 430 and its winding, over the No. 5alternate contacts of relay 4|8, conductor 235, the No. 3 contacts ofrelay 204, conductor 236, the No. '1 contacts of relay 4|8, to ground atthe No. 2 front contact of relay 4| 2. On the third closure of 'thecontacts of interrupter 505 the previously traced circuit for relay 423is established whereupon it reoperates but relay 424 being shunted overits own No. '1 back contact does not operate at this time. With relay4|1 now operated the circuit over which coin return current was appliedto the coin box is opened at the No. 1 back contact of relay 4|1 and the-capacity discharge of the calling line is established over the tip andring conductors of the calling line eX- tended through the operation ofrelay 204 t0 the Nos. 1 and 8 back contacts of relay 229 and thencethrough resistances 230 and 23| and condenser 232 to ground.

Upon the third opening of the contacts of inter- A rupter 505, the shuntof the Winding of counting relay 424 is opened and relay 424 operatesover the previously traced circuit. Upon the fourth closure of thecontacts of interrupter 505, relay 423 is shunted down in the mannerpreviously described and a shunt of the Winding of relay 4|8 isthereupon established from a point between its winding and resistance429, over the No. 7 front contact of relay 4|1, the upper back contactof relay 423, conductor 235, the No. 3 contacts of relay 204, conductor236, the No. 4 contacts of relay 424, to ground at the No. 2 frontcontact of relay 4 I 2. A circuit is now established from batterythrough the winding of relay 406 over conductor 433, the No. 6 backcontact of relay 200, conductor 231, the No. 3 back contact of relay4|8, the No. 8 conta-cts of relay 4|1 to ground over the No. 6 contactsof relay 40| whereupon relay 406 operates, locks over its No. 5 contactsto ground over the No. 6 contacts of relay 40| and establishes a circuitfrom battery through the winding of relay 229, over conductor 238, theNo. 4 contacts of relay 406, the No. 4i contacts of relay 4|1, the uppercontacts of relay 401, to ground at the No. 8 back contact of relay 400.Relay 229 upon operating locks over its No.

5 contacts, conductor 239 to ground at the inner lower front contact ofrelay 401; disconnects the calling line discharge -circuit at its Nos. 1and 8 back contacts; opens the circuit over which relay 228 wasenergized at its No. 2 and No. 7 back contacts; opens at its No; 7 backcontact the circuit over which the tone current from the tone Source 409was applied to the cord circuit; connects the tip conductor of thecalling line as traced over the No. 8 front contact of relay 204, thenceover its No. 8 and No. '1 front contacts, conductor 240 and theu tips ofjack 2|9 and the cord circuit plug to the tip conductor of the cordcircuit and connects the ring conductor of the calling line as tracedover the No. 2 front Contact Q Iilay 204,

thence over its Nos. 1 and 2 front contacts, conductor 24| and the ringsof jack 220 and the cord circuit plug to the ring conductor of the cordcircuit.

Uponk the fourth opening of the contacts of interrupter 505 the holdingcircuit of counting relay 424 is opened and relay 424 now releases inturn opening the holding circuit of relay 4|1 at its No. 4 contacts.With relay 424 released and relay 229 operated, relay 4|2 now releasesand establishes a discharge path for condenser 232 through the 1600 ohmresistance 23|, over conductor 4|6 to ground at the No.' 2 back contactof relay 4|2.

Checking the deposit of coins requested for initial period With relay229 operated the operator may now talk with the calling person andrequest'him to deposit the amount indicated by the lamp 224 which waspreviously lighted, or ten cents, to cover the initial ve-minute periodof the conversation. Upon hearing the tone indicative of the deposit ofthe requested amount the operator disconnects her cord circuit from thejack 2|9 thereby releasing relay 401. The approximate time which haselapsed from the time the operator answered the call to operate relay401 and the operation of relay 229 to connect her headset with thecalling station is between 1.2 and 1.7 seconds. When relay 401 releasesit in turn releases relays 204, 229 and 408. Relay 204 upon releasingagain connects the windings of relay 2|3 to the calling line andrestores supervision to the tandem trunk and relay 408 upon releasingestablishes the circuit of relay 200 which may be traced from batterythrough its winding over conductor 242, the No. 8 contacts of relay 406,the No. '1 back contact of relay 408, conductor 2||, the inner upperback Contact of relay 500, conductor 2 I2 to ground at the No. 3 normalcontacts of relay 400. Relay 200 upon operating locks over conductor242, the No. 8 contacts of relay 406, conductor 243, its own No. 5contacts to ground on conductor 2|2; opens the circuit of relay 20| atits No. '7 back contact whereupon relay 20| releases and over its Nos. 2and 8 front contacts completes a talking circuit between the callingline and outgoing conductors 302 and 303 of the tandem trunk and bridgesthe winding of polarized supervisory relay 244 across such outgoingtrunk conductors. Relay 202 upon releasing opens at its No. 1 contactsthe connection to thesleeves of trunk jacks 2|9 and 220 to preventinterference with the call should the operator plug into one of suchjacks in error.

Completion of the desired connection With relay 200 operated a circuitis established from battery through the winding of relay 32| at thetandem sender, over the lower normal contacts of relayi`320, the upperalternate contacts of relay 301, the back contact of relay 306, contactsof cam 305, trunk conductor 302, the No. 8 front contact of relay 200,the winding of polarized relay 244, the No. 2 front contact of relay200, trunk conductor 303, contacts of cam 3 I3, the back Contact ofrelay 3 2, the inner lower alternate contacts of relay 301, the uppernormal contacts of relay 320 to ground through the winding of relay 322at the tandem sender. The current flowing over this circuit through thewinding of polarized supervisory relay 244 is in such a direction as tooperate its armature against its right contact. Relays 32| and 322 atthe tandem sender are now both operated in turn operating relays 323 and324. With relay 324 operatedV the circuit of relay 325 is opened at itsback contact and relay 325 releases to make the Start circuit for timingout the tandem sender operative to function in the usual manner. Acircuit is also established from ground over the lower front contacts ofrelays 323 and 324 through thewinding of relay 321 to battery, whereuponrelay 321 operates, locks in a circuit over its lower contacts, theinner upper contacts of relay 326 and the upper front contacts of relays324 and 323 to ground. Relay 336 is also operated in a circuit frombattery through its winding over the upper front contacts of relays 323and 324 to ground and upon operating locks over its lower front contact,the lower front contact of relay 321 to ground over the lower contactsof relay 321 and the lower contacts of relay 324 and relay 323, Relay321 upon operating opens the locking circuit of relay 326 whichthereupon releases in turn opening the locking circuit of relay 321 butrelay 321 isnow held operated under the control of relays 323 and 324and relay 336 over a locking circuit extending over its lower frontcontacts, the lower front contacts of relay 336 to ground over the upperfront contacts of relays 323 and 324. With relay 321 operated thefundamental circuit is established over its upper contacts through thewinding of trunk test relay 331, contacts of cams 338, 339 and 341 ofthe sender and contacts of cams 340 and 34| in the tandem districtselector. The tandem sender now proceeds to complete the desiredconnection in accordance with the digital information registered thereinin the usual manner. When the connection is completed the tandem senderis dismissed and the sequence switch of the tandem district selector isadvanced to the trunk closure position in which position a circuit isestablished from battery through the left winding of relay 342, theupper back contact of relay 343, the upper left winding of repeatingcoil 344, contacts of cam 305, trunk conductor 302, the No. 8 frontconta-ct of relay 200, the winding of relay 244, the No. 2 front Contactof relay 200, conductor 303, contacts of cam 3|3, the lower nleftwinding of repeating coil 344, the lower back contact of relay 343 toground through the right winding of relay 342. The direction of thecurrent iiowiner is still in such a direction as to hold the armature ofrelay 244 against its right contact.

Response of the called subscriber When the called subscriber answers, acircuit is completed which may be traced in part over the contacts ofcam 34|, through the upper right winding of repeating coil 344, windingof supervisory relay 345, contacts of cam 346, the lower right windingof repeating coil 344 and the upper contacts of cam 346 to cause theoperation of relay 345 followed by the operation of reversing relay 343.Relay 343 upon operating reverses the connections of battery and groundthrough the windings of relay 342 to the trunk conductors 302 and 303whereby current new flows in such a direction through the winding ofpolarized relay 244 to cause the movement of its armature intoengagement with its left contact. As soon thereafter as interrupter cam508 closes its left contact a circuit is established from ground overthe No. 4 contacts of relay 200, the left contact of relay 244,conductor 245, left contact of interrupter 508, conductor 520 to batterythrough the winding of relay 434 which thereupon operates and locks overits inner upper contacts to ground applied to conductor 245 by relay244. As soon thereafter as interrupter 508 closes its right contactrelay 434 establishes a circuit for relay 5|8 which may be traced frombattery through its winding, over conductor 52|, the No. 5 back contactof relay 435, conductor 522, contacts closed by cam 50| of the chargetimer 550, which timer is in its normal position, conductor 523, the No.4 back contact of relay 435, the lower front contact of relay 434,conductor 524, over the right contact of cam 508 to ground on conductor245.

' Relay 5|8 upon operating locks in a circuit eX- tending from batterythrough its winding, over conductor 52|, the No. 5 back contact of relay435, conductor 522, the No.k 8 contacts of relay 5|8, conductor 525, theNo. 5 back contact of relay 4|1 to ground over the No. 6 contacts ofrelay 406; connects ground over its No. 4 contacts to conductor 405 tohold relay 40| operated; establishes an operating circuit for relay 5|2which maybe traced from battery through its winding, over conductor 2|5,the No. 3 front `Contact of relay 200 and conductor 246` to ground overthe No. 6 contacts of relay 5|8, and starts the charge timer 550 formeasuring the initial period for conversation by operating clutch magnet504. The circuit of magnet 504 may be traced from battery through itswinding, over conductor 526, the No.V 6 back contact of relay 435,conductor 521, the No. 3 contacts of relay5|8 to ground at the No'. lback contact of Yrelay 528.v

The energization of magnet 504 causes a gear train to engage with ashaft driven by a telechron motor. Four and one half minutes lateracircuit is established for relay 4|2 which may be traced from batterythrough its winding over conductor 4|3, the No. 6 back contact of relay220, conductor 4|5, the contacts closed by timer cam 502, to ground overthe No. 2 contacts of relay 5|8. Relay 4|2 upon operating connectsground to one contact controlled by the interrupter cam 505, connectsthe two -ohn1 resistances 5|4 and 5|5 across the calling line andremoves ground applied over conductor 4 5 from the line dischargenetwork comprising resistances 230 and 23| and condenser 232 lin amanner described in connection with its previous operation. Under thecontrol of interrupter 505, counting relay 423 is operated upon the rstclosure of the interrupter contacts and prepares the operating circuitof counting relay 424 which thereafter operates upon the followingopening of the interrupter contacts. With relays 423 and 424 bothoperated resistance 5 |'5 is short-circuited thus reducing theresistance bridged across the calling lineV to 50 ohms and relay 500 isoperated to shunt resistance 5|4 thus further reducing the bridgedresistance to Zero. The application and reduction of the shunt acrossthe calling line is for the purpose of diverting the current from theline prior to the connection of coin control battery thereto in order toprevent disturbances from reachingthe called subscriber through thetandem and terminating office equipment. Upon the second closure of thecontacts of interrupter 505, relay 423 is released and relay 424 islocked in its operated condition. The operating circuit of relay 500 isnow opened and the operating circuit of relay 204 is closed todisconnect the windings of relay 2|3 from the calling line while it isstill short-circuited; to lock itself operated over conductor 421 andthe'No. 6 contacts of relay 4|2, under. the control of relay 435; totransfer trunk conductors 205 a'nd206 in preparation for Lcoincollection and to establish the operating circuit of counting relay 4|8which thereupon operates. These functions are all performed in themanner previously described.

Collection of coins deposited for initial period With relay 4|8operated, coin collecting battery is connected from the source 529 overthe No. 5 back contact of relay 528, conductor 530, the No. 3 backcontact of relay 435, conductor 536, the No. 5 contacts of relay 5|8,conductor 53|, the No. 1 back contact of counting relay 4|1, the No. 4co-ntacts of relay 4|8, conductor 43|, over the Nos. l and 8 backcontacts of relay 229 and the Nos. 2 and 8 front contacts of relay 204,thence over the tip and ring conductors of the established connectie-nthrough the magnet of coin box to ground over contacts closed thereat bythe deposited coin or coins. The coin boxmagnet is now energized in sucha manner as to transfer the previously deposited coin or coins to thecoin box till. Upon the second opening of the contacts associated withcam 505, relay 424 is released and relay 4|1 is operated in the mannerpreviously described to open the circuit over which coin collectingcurrent was applied to the coin box |0|. Upon the third closure of thecontacts associated with cam 505, relay 423 again operates and withrelay 4| 1 operated the capacity charge of the calling line isdissipated over the tip and ring conductors of the line extended throughthe operation of relay 204 to the Nos. 1 and 8 back contacts of relay229 and thence through resistances 230 and 23| and condenser 232 toground.

Upon the third opening of the contacts of interrupter 505, relay 424operates and upon the fourth closure of the interrupter contacts relay423 releases in turn releasing relay 4|8 in the manner previouslydescribed. A circuit is now established for relay 435 which may betraced from battery through its winding over conductor 431, the No. 6front contact of relay 200, conductor 231, the No. 3 back contact ofrelay 4|8, the No. 8 contacts of relay 4|1 to ground over the No. 6contacts of relay 40|. Relay 435 upon operating locks in a circuittraced throug-h its winding to conductor 231, thence over its No.2contacts, the No. back contact of relay 408 to ground over the No. 6contacts of relay 40|, opens the locking circuit of relay 204 at its No.1 back contact whereupon relay 204 releases to reconnect the windings ofrelay 2|3 to the calling line and at its No. 5 back contact opens thelocking circuit of relay 5| 8 which thereupon releases. Upon the fourthopening of the contacts of interrupter v505, relay 424 releases followedby the release of relays 4|1 and 4|2 as previously described. Relay 4|2upon releasing discharges condenser 232 through the 160Q-ohm resistance23|. Relay 204 has been operated for an interval of 1.2 to 1.7 secondsduring the collection of the deposited coin or coins and no tone currenthas been transmitted to the calling line when the coins are collected toavoid encouraging the calling person to deposit further coins.

The charge timer 550 continues its operation until the normal contactsassociated with its cam 50| close ve minutes after relay 5|8 operated atwhich time a circuit is established from battery through the winding ofovertime relay 528, conductor 532, the No. 4 iront contact of relay 435,conductor 523, closed contacts associated with cam 50|, conductor 522,the No. 5 front contact of relay 435', conductor 245, the left contactof relay 244 to ground over the No. 4 contacts of relay 200 if theconversation still continues and relay 244 has therefore remainedoperated. Relay 528 upon operating locks over its No. 3 contacts andconductor 533 to ground over the No. 6 contacts of relay 40|;establishes a circuit from battery through the winding of relay 2|1,over the upper contacts of relay 2|3, conductor 2|8, the No. 4 contactsof relay 528, over contacts associated with interrupter cam 505,conductor 534, the No. 1 contacts of relay 40| to ground at the backcontact of relay 401 whereby relay 2|1 is intermittently operated; andestablishes a circuit from the sleeves of jacks 2|9 and 220 overconductor 4| the No, 2 contacts of relay 528, conductor 535, the No. 2contacts of relay 40| to ground through the winding of relay 401. Relay2|1 upon operating and releasing intermittently, ashes the lamp 224ovei` the previously traced circuit as a signal to the operator that theovertime period on the established connection has been reached.

Overtime response of an operator The operator answers the hashing lampby inserting the answering plug of one of her cord circuits into thejack 2|9 associated with such flashing lamp whereupon relay 461 operatesfollowed by the operation of relay 228. Relay 401 upon operating opensthe circuit of relay l2|1 whereby the flashing lamp 224 is extinguishedand establishes the circuit of relay 408 which thereupon operates toconnect the tone source on conductor 409 to the operators position towarn the operator not to commence a conversation with the callingperson; opens the locking circuit of relay 435 at its No. 5 back'contact which relay thereupon releases; establishes a circuit for relay4|2 which may be traced from battery through its Winding over conductor4|3, the No. 6 back contact of relay 229, contacts of relay 228,conductor 4|4 to ground over the No. 6 contacts of relay 408 and closesthe sleeves of jack 2|8 and 220 directly to ground through the windingof relay 401, over its No. l contacts. Relay 435 upo-n releasingreestablishes the previously traced operating circuit for relay 5|8 uponthe next closure of the right contact of inter rupter 508 if the calledsubscriber has not disconnected and relay 4|2 upon operating locks overconductor 4|3, the No. 6 back contact of relay 229, conductor 4|5, theNo. 4 contacts of relay 4|2 to ground over the No. 6 contacts of relay408; connects the resistances 514 and 5|5 across the calling line in acircuit which may be traced from trunk conductor 205 over the No. 8 backcontact of relay 204, the No. 1 front contact oi relay 203, conductor420, through resistances 5|4 and 5|5, conductor 4|9, the No. 3 contactsof relay 4|2, the No. 2 back contact of relay 4|8, the No. 6 backcontact of relay 4|1, conductor 233, the No. 3 back contact of relay229, the No. 1 front contact of relay 203 and the No. 2 back contact ofrelay 284 to trunk conductor 206; at its No. 2 back contact removesground from the line discharge network comprising resistances 230 and23| and condenser 232 and connects ground over its No. 5 contacts andconductor 42| to one of the contacts of interrupter 505. In response tosubsequent closures and openings of the contacts of interrupter 505,counting relays 423 and 424 are operated and released in the mannerpreviously described.

Under the control of interrupter 505 relay 423 is operated upon thefirst closure of the interrupter contacts and prepares` the operatingcircuit of relay 424 which thereafter Operates upon the followingopening of the interrupter contacts.

With relaysV 423 and 424 both operated, resistsistance to Zero. Upon thesecond closure of the contacts of interrupter 505, relay 423 is releasedand relay 424 is locked in its operated condition. The operating circuitof relay 500 is now opened and the operating circuit of relay 5204 isclosed to disconnect the windings of relay 2I3 from the callingline'while it is still short-circuited; to

lock itself operated over its No. 5 contacts and conductor 421 to groundover the lower contacts of relay 401; to transfertrunk conductors 205and 206 to the Nos. 8 and 1 contacts of relay 229 preparatory toestablishing a talking circuit with the operators cord circuit; toprepare the locking circuit of relay .403 and to establish the operatingcircuit of counting relay 4I8 which thereupon operates. These functionsare performed in the manner previously described.

With relay 4 I 8 operated, a circuit is established from battery throughthe winding of relay 229 over conductor 238, the No. 4 contacts of relay406, the No. 1 contacts of relay 4I8, the upper f contactsof relay 401to ground at the No. 8 back contact of relay 400. Relay 229 uponoperating locks over its No. 5 contacts andv conductor 239fto'groundover Vthe inner lower front contact of relay 4.01; discontinues theapplication oftone current from the source 409 to the operatorsheadset;` opens the: operating circuit .of relay 4l2'leaving itroperated under the control of relay 424 and at its Nos. 1, 2, 1 and 8front contacts cuts through a talking connection from the calling lineto the' operators cord circuit. Upon the second opening of the contactsof' interrupter 505, relay 424 releases and counting relay 4I1 isoperated in the manner previously described, whereupon relay 4i2releases. relays 4I2 and 424 released, relay 4I8 releases. The callingline is now in a similar relation to the operators cord circuit as itwould be on a connection established in the usual manner withy theoperators position by dialing zero; the operator being able to talk withthe calling person over the connection just traced over the front,contacts of relays 204 and 229, collect or return coins by the use ofthe collect or return keys of her position, receive supervision andcontrol ringing. The interval from the interruption of the conversationby the operation of relay 204 until the operator is connected is from .2to .'1 of a second. The connection between the trunk conductors 205 and206 and the outgoing trunk` conductors 302 and 303 extends over frontcontacts of relays 204 and 229 and the outer back contacts of splittingrelay 241 and thus a threeway talking connection is effected. Anappreciable transmission loss is produced while the talkingikey ofthecord circuit is operated but with this key normal the loss isnegligible.

The operator upon conversing with the calling person informs him thatthe initial period for conversation for which he has previouslydeposited coins has expired. She may then follow either of two differentlines of procedure dependent upon the '-traflic regulations set up bythe operating company, that is, she may request;

With

the calling person to deposit the required number of coins for theovertime period if he desires to continue the conversation and make outa ticket whereby she may time the call, or she may request the callingperson to signal her when he has terminated the conversation after whichshe will inform him as to the additional coins which he should depositfor the elapsed overtime period and she will also make out a ticketwhereby she may time the call. Should she follow the first procedure andth calling party fail to deposit the required coin or coins for theovertime `period `iust beginning, she may insert a cord circuit pluginto the operating jack 249'thereby establishing a circuit over thesleeves of the cord circuit plug and jack, over the No. 4 contacts ofrelay 229 to ground through the winding of relay 241 whereupon relay 241operates; locks directly to the jack sleeve; at its back contacts opensthe talking connection between the calling and called lines and at itsouter front contacts establishes a talking connection from her cordcircuit plugged into the splitting jack 249 to the talking connectionextending to the called line. The operator can now talk to either thecalling person or the called subscriber at will but the calling personand the called subscriber cannot talk to each other. If the callingperson deposited the required coins the operator may make out a ticket,time the call and at the 'expiration of one or more overtime periodsrequest the calling person to deposit additional coins for theadditional overtime period or periods if he desires to continue theconversation. The provision of the splitting jacks enables the operatorto `break in open the conversation at any time during the overtimeperiod.` Ordinarily, she would not do so on calls for which the chargerate is more than fifteen cents because on such higher rate calls theovertime periods might be as short as one or two minutes and it wouldnot be desirable from a service standpoint to interrupt the conversationfrequently.

Should `the operator follow the second procedure, she will make out aticket when she has ascertained that the calling person desires tocontinue the conversation and will .time the call. When she receives asignal from the calling person that he has terminated the conversation,she

may then inform him from the elapsed time noted on the ticket as to theamount in coins he should deposit for the overtime period or periods ofconversation.

It will be obvious that the circuits could with very slight modificationbe arranged to automatically time each overtime period and to call inthe operator at the expiration of each time period to request thedeposit of an additional coin or coins for the next overtime period.

Disconnection If the calling person abandons the connection and throughsome trouble condition the district selector |05 or the districtjunctorof a crossbar oirlce releases without waiting for the originating senderto transmit the final heavy positive impulse to operate relay 202, relay203 will not be operated and therefore the lockingl circuit for relay II5 will extend as 'previously traced over conductor IIB vand the No. 5normal contacts of relay 203 to the sleeve conductor II1. When ground isremoved from the sleeve conductor I I1 at the oflice selector |06 uponits release follow'-v ing the release ofthe district selector |05, relayI I5 releases followed by the release of relay H2 thus restoring thetrunk circuit to normal. The

release of apparatus at the tandem ofce follows in the usual manner.

If disconnection should occur as the district selector goes through itstrunk closure position while awaiting the response of the operatorinitially or between the 41/2 minute interval and the beginning of theovertime interval and before relay 5|8 has operated, relay 2|3 willrelease. It

will be assumed that the disconnection occurs .between the 41/2 minuteinterval and the response of the operator. When relay 2|3 releases,relay 403 releases and a circuit is established from battery through thewinding of relay 400, the No. 8 contacts of relay 40| to ground at theback contact of relay 403. Relay 400 upon operating locks over its No. 1contacts and conductor 438 to ground over the No. 4 contacts of relayI|2; establishes a holding circuitl for relay ||5 which may be tracedfrom conductor I I6, over the No. 5 alternate contacts of relay 203, theNo. 4 back contact of relay 204, conductor 241 to ground over its No. 8front contact; at its No. 5 back contact opens the operating circuit ofrelay 403 thereby locking in the disconnect condition; at its No. 3 backcontact opens the locking circuit of relay 200 which thereupon releases;and establishes the circuit of relay 500 which may be traced frombattery through its winding over conductor 5|6 to ground over the No. 2contacts of relay 400. Relay 200 upon releasing opens the trunk towardthe tandem district selector thereby initiating the release of theconnection to the called line;

' releases relay 244 if operatedV and releases relays 435 and 5|2. Relay244, upon releasing, releases relay434. With relay 500 operated, acircuit is established for operating relay 204 which may be traced frombattery through the Winding of relay 204 over conductor 234, the No. 4contacts of relay 400, conductor 421 to ground over the inner upperfront contact of relay 500. Relay 204, upon operating, locks directly toground over conductor 421 and the front contacts of relay 500; opens thelocking circuit of relay 40| at its No. 7 back contact; establishes ashort circuit between trunk conductors 205 and 206 over its Nos. 2 and 8front contacts and the Nos. 1 and 8 back contacts of relay 229 toblock atrunk test on any new call and opens the locking circuit of relay ||5 atits No. 4 back contact whereupon relay ||5 releases together with relayRelay -40| upon releasing opens the holding circuit of relay 406 at itsNo. 6 contacts whereupon relay 406 releases and relay I5 upon releasingreleases relay ||2 followed by the release of relays 203 and 400. Relay203 upon releasing removes busy ground from the sleeve conductors ||1and ||8 and relay 400 upon releasing releases relay 500 followed by therelease of relay 204.

If a disconnection occurs before trunk closure at the district trunk|03, relays 2|3 and 403 operate on the trunk closure in the sender |04and relay 403 locks in a circuit from battery through its winding, overthe No. 5 back Contact of relay 400, over its own upper contacts, theNo. 5 normal contacts of relay 40|, conductor 404 to ground over the No.7 back contact of relay 204. When relay 40| operates following theoperation of relay 403, relay 403 will release if relay 2|3 is no longeroperatedA or when relay 2 |3 releases if the trunk closure has notended. From this point the release of the trunk proceeds as justdescribed eXcept that certain relays are not operated and need nottherefore be released. The lamp 224 or 226 may flash at the Aswitchboard but this is held to a minimum by controlling the circuit ofrelay 2|1 over front contacts of both relays 2|3 and40l.

If a disconnection occurs while awaiting the initial answer of theoperator, the operation is similar to that described except that relay20| is operated thereby holding the tandem sender from releasing. Whenrelay 400 operates as pre- Vioulsly described relay 20| is releasedinstead of relay 200 and the tandem circuit then proceeds to releaseimmediately.

If a disconnection occurs after relay 200 has operated but before thecalled subscriber has answered or on a busy back condition the operationis similar to that described except that relay 435 is not operated.

There are two disconnect conditions which may arise after relay 5|8 hasoperated and with no operators vcord circuit plugged into a trunk jack;one between the initial operation of relay 5|8 and the closure of the41/2 minute contacts associated with YCam 502 of the charge timer 550,and the other after the operator has disconnected following the start ofthe overtime interval. This latter condition occurs only if relay 244has operated and the operator answers at the beginning of the overtimeinterval. Relay 2|3 releases when the calling person disconnects, orfails t0` operate when the operator withdraws her cord circuit plug fromthe trunk jack 2|9 or 220. Relay 403 then releases and relay 400operates locking over its No. 1 contacts to ground over the No. 7contacts of relay 40| and over conductor 438 to ground over the No. 4contacts of relay I|2; supplying a holding circuit for relay I 5;opening the operating circuit for relay 403 to lock in the disconnectcondition; releasing relay 200 and operating relay 500 in the mannerpreviously described. Relay 200 upon releasing opens the trunk towardthe tandem oiiice, releases relay 244 if operated, and releases relay5|2. With relay 244 released, relay 434 is released. Relay 500 uponoperating causes the operation of relay 204 in the manner previouslydescribed whereupon the trunk conductors 205 and 206 are connected overits Nos. 2 and 8 front contacts and the Nos. 1 and 8 back contacts ofrelay 229 to the line discharge network comprising resistances 230 and23| and condenser 232; locks itself under the control of relay 500 andestablishes the circuit of relay 4|2 which may be traced from battery INo. 4 front Contact of relay 204, conductor 241 to ground over the No. 8front contact of relay 400. From this point the operation is practicallythe same as previously described in connection with the collection ofthe deposited coin for the initial period of conversation except thatrelay Relay H5 upon releasing releases relay |I2 and relay 40| uponreleasing releases relay 406 which in turn at its No. 'l contactsremoves ground from conductor 440 to release the timer if the pick-upcontacts associated with cam 503 are closed. With 20|- operatedfollowedV by ythe operation of 'relay relay f |12 Vreleased theV vtrunkcircuitl releasesv to normal as previously described.

If disconnection occurswhile a cord. circuit is plugged into jack 2 9 or220 the answering supervisory lamp at the cord circuit will be lighted;The operator then collectsthe coins remaining in the coinv box: orv ifnecessaryringsthe calling sta'.- tion' toobtain any money due and thenwithdraws the cord plug thereby releasing relay 401. Relay 401 uponreleasing releases relays 204 andVY 229 and releases relay 408 if nocord. circuit has been plugged into one of the splitting'jacks 249 or250'. Relay 2|3 will not reoperate when' relay 204 releases and thecircuit will proceed to release as previously described.

Should the calling person abandon the call Without replacing thereceiver on the switchhook at the calling station, the operator mayrelease the connection when she answers the initial lighting of one ofthe trunk lamps 224 or 226. When vshek can obtain no response from thecalling person although the receiver is still off the switchhook, a cordcircuit is momentarily inserted into one of thesplittingjacks 249 or 250thereby causing the operation of relay 241. Relay 400 is now operated atonce` over a circuit which may be traced from battery through thewinding of relay 400 over conductor 442, the No. 2 contacts of relay 20|to ground over the inner upper contacts of relay 241 andlupon operatingreleases relay 20| and the tandem oilice circuits. When the.

operator withdraws the cord circuit, from the answering jack the circuitreleases' as on a regular disconnection before the operator answersexcept that relay 20| is already released.

Timed release 5| I, the inner lower contacts of relay 5|2, con

ductor 539 the right contact of relay 244 to ground over theNo. lcontacts of relay 200; locks over its lower-contacts to its operatingcircuit independent of thecontacts of interrupter 5| and closes acircuit from battery through the winding of relay 540, over its uppercontacts* as soon as the contacts associated with interrupter cam 5 I 0close. With relays 5|2 and 540 both operated a circuit is establishedfrom ground over contacts of relay 540, the middle lower contacts ofrelay 5|2, conductor 54|, the lower back contact of relay 201, conductor44|, the back contacts of relay .434 to battery through the winding ofrelayv 400. The trunk then proceeds to release in the manner previouslydescribed except that if a cord cir'-y cuit has been plugged into one ofthe jacks 2|9 or 220, only the tandem ollice equipment is releasedimmediately. In this case when the operator withdraws the cord plug,relay 403 is already released and relaysr400, 500 and 203 are operated.It is to be noted that the interrupters 5|0Y and 5|| and relays 538 and540 constitute a timed release control equipment common to live trunks.

Trunk closure fuz'Zure It wiu be recaued that at the 'end of thetransmission of the final heavy positive impulse, relay 5|2 as soonthereafter 'as interrupter cam 501 closesV its left contact. `WithVrelay 5|2 operated,

iftrunk closure is not completed by the time cam' Time alarm circuit Thetime alarm circuit comprisingr the interrupter cam 509, relays 544 and545, lamp 546 andV key 541 is provided for each group of ve trunks.Whenever either relay 400 or 4|2 operates with relay 408 released atiming cycle is started' in order to check that the circuit can releaseand control coins properly. The circuit for starting theV timing cyclemay be traced from battery throughv thewinding of relay 543, overconductor 548, the No. 4 back contact of relay 408, over the No. 1 frontcontact of relay 4I2 or the No. 6 front contact of. relay 400, conductor549, the upper normal contacts of relay 543, the back contact of relay544 to ground over the back contact of relay 545. Relay 543, which isindividual to the trunk, upon operating locks itself over its upperalternate contacts independent of relays 544 and.

545 and establishes a circuit from ground over its inner contacts andthe right contact of inter- Relay 545 upon operatinglocks under thecontrol' of alarm release key 541, establishes an alarm circuit over itsinner lower front contact, lights the alarm lamp 546 and opens a furtherpoint in theoperating circuits of relay 543 and similar relays.

In some exchange areas the initial deposit of a coin to `initiate thestarting of a call is not re-' quired, but the completion of theconnection isH arrested, for example, just prior to the units selectionoperation of the nal selector, until the callingr subscriber hasdeposited a coin. With this mode of procedure a calling subscriber maymake emergency calls to an operator even though hehas no coin of thesuitable denomination forv depositin the coin box. They trunk circuit ofthe present invention will function equally well in exchange areas ofthis character.

What is claimed is: f 1. In atelephone system, a rst oilice, a coin'box'- line terminating' therein, a tandem oilice, terminating offices,switching mechanism in said oces, control means in said tandemollce, an

operators position having cord circuits in said first olhce,x a trunkextendingbetween said firstv and said tandem oilices having a separateappearance in the switching mechanism of said first ofce and acorresponding` lampand jack appearance' at said operators position foreach of a plurality of charge rates for calls from said line to desiredlines terminating in said terminating oices, means operated upon theseizure of said trunk to prepare said control means for controlling thecompletion of the desired connection and for lighting the lamp at saidoperators position indicative of the charge rate for the desiredconnection, means operative following the connection of a cord circuitof said position to the jack associated with the lighted lamp forenabling the operator to request and to checkthe deposit of the requiredcoin or coins, and means responsive to the disconnection of said cordcircuit from said jack for signaling said control means to proceed withthe control of the completion of the desired connection.

2. In a telephone system, a iirst oilice, a coin box line terminatingtherein, a tandem office, terminating 'orlices, switching mechanism insaid oices, control means in said tandem oice, an operators positionhaving cord circuits in said iirsl-l omce, a trunk extending betweensaid first and said tandem oices having a separate appearance in theswitching mechanism of said rst oice and a corresponding lamp and jackappearance at said operators position for each of a plurality of chargerates for calls from said linefto desired lines terminating in saidterminating oflices, means operated upon the seizure of said trunk toprepare said control means for controlling the completion of the desiredconnection and for lighting the lamp of said operators positionindicative of the charge rate for the desired connection, meansoperative in response to the connection of a cord circuit of saidposition to the jack associated with the lighted lamp for refunding thecoin initially deposited in the coin box of said calling line, meansthereafter effective to enable the operator to request and to check thedeposit of a coin or coins in payment for the initial period ofconversation, and means responsive to the disconnection of said cordcircuit from said jackY for signaling said control means to proceed withthe control of the completion of the desired connection. i

3. In a telephonel system, a rst oice, a coin box line terminatingtherein, a tandem office, terminating offices, switching mechanism insaid oiiices, control means in said tandem office, an operators positionhaving cord circuits in said first oflice, a trunk extending betweensaid rst and said tandem offices having a separate appearance in theswitching mechanism of said iirst oiiice and a corresponding lamp andjack appearance at said operators position for each of a plurality ofcharge rates for calls from said line to desired lines terminating insaid terminating offices, means operated upon the seizure of said trunkto prepare said control means for controlling the completion of thedesired connection and for lighting the lamp at said operators positionindicative of the charge rate for the desired connection, meansoperative in response to the connection of a cord circuit of saidposition to the jack associated with the lighted lamp for refunding thecoin initially deposited, means effective a measured interval thereafterfor discharging the capacity charge from said cord circuit from saidjack for signaling said" control means to proceed with the control oftheV terminating offices, switching mechanism in said ofces, controlmeans in said tandem office, an operators position having cord circuitsin said iirst oice, a trunk extending between said first and said tandemoffices having a separate appearance in the switching mechanism of saidrst oice and a corresponding lamp and jack appearance at said operatorsposition for each of a plurality of charge rates for calls from saidline to desired lines terminatingl in terminating orlices, meansoperated upon the seizure of said trunk to'prepare said control meansfor controlling the completion of the desired connection and forlighting the lamp at said operators position indicative of the chargerate for the desired connection, means operative following theconnection of a cord circuit of said position to the jack associatedwith the lighted lamp for enabling the operator to request and to checkthe deposit of a coin or coins in payment'for the initial period ofconversation, means responsive to the disconnection of said cord circuitfrom said jack for signaling said control means to proceed with thecontrol of the completion of the desired connection, and means operativea predetermined interval following the response of the called subscriberfor causing the collection of the deposited coin or coins.

5. In a telephone system, a first olice, a coin box line terminatingtherein, a tandem office,

terminating offices, switching mechanism in said offices, control meansin said tandem ofce, an operators position having cord circuits in saidrst omce, a trunk extending between said rst and said tandem ofliceshaving an appearance in the switching mechanism of said first oice and alamp and jack appearance at said operators position for each of aplurality of charge rates for calls from said line to desired linesterminating in said terminating offices, means operated upon the seizureof said trunk to prepare said control means for controlling thecompletion of the desired connection and for lighting the lamp at saidoperators position indicative of the charge rate for the desiredconnection, means operative in response to the connection of a cordcircuit of said position to the jack associated with the lighted lampfor refunding the coin initially deposited in the coin box of saidcalling line, means thereafter ellective to enable the op- .erator torequest and to check the deposit of a coin or coins in payment for theinitial period of conversation, means responsive tothe disconnection ofsaid cord circuit from said jack for signaling said control means toproceed with the control of the completion of the desired connection,and means operative a predetermined interval following the response ofthe called subscriber for causing the collection of the last depositedcoin or coins.

6. In a telephone system, a rst oflice, a coin box line terminatingtherein, a tandem oilice, terminating oiices, switching mechanism. insaid offices, control means in said tandem oflice, an operators positionhaving cord circuits in said first oiice, a trunk extending between saidrst and said tandem oflices having an appearance in the switchingmechanismA of said rst oiiice and a lamp and jack appearance at saidoperators position for each of a plurality of charge rates for callsfrom said line to desired lines terminating in said terminating ofiices,means operated upon the seizure of said trunk to prepare said controlmeans for controlling the completion of the desired connection 'and forlighting the lamp at said operators position indicative of the chargerate for the desired connection, means operated in response totheconnection of a cord circuit of said position to the jack associatedwith the lighted lamp to enable the operator to request and to check thedeposit of a coin or coins in payment for the initial period ofconversation, means responsive to the disconnection of said cordcircuitfrom said jack for y signaling said control means to proceed withthe control of the completion of the desired connection, means operativeupon the response of the called subscriber to start the measurement ofan initial period for conversation, means effective just prior to thetermination of such period for causing the collection of the depositedcoin or coins, and means operative at the end of such period for ashingthe lamp previously lighted to inform an operator that said initialperiod has terminated.

7. In a telephone system, a rst oiiice, a coin box line terminatingtherein, a tandem ofce, terminating oi'lices, switching mechanism insaid oces, control means in said tandem oice, an operators positionhaving cord circuits in said first oice, a trunk extending between saidiirst and said tandem oiTices having an appearance in the switchingmechanism of said rst oice and a lamp and jack appearance at saidoperators position for each of a plurality of charge rates for callsfrom said line to desired lines terminating in said terminating offices,means operated upon the seizure of said trunk to prepare said controlmeans for controlling the completion of the desired connection and forlighting the lamp at said operators position indicative of the chargerate for the desired connection, means operated in response to theconnection of a cord circuit of said position to the jack associatedwith the lighted lamp to enable the operator to request and to check thedeposit of a coin or coins in payment for the initial period ofconversation, means responsive to the disconnection of said cord circuitfrom said jack for signaling said control means to proceed with thecontrol of the completion of the desired connection, means operativeupon the response of the called subscriber to start the measurement ofan initial period for conversation, means effective justv prior to thetermination of such period for -causing the collection of the depositedcoin or coins, means operative at' the end of such period forilashingthe lamp previously lighted, and means responsive to theconnection of a cord circuit to the jackv associated with the flashinglamp to enable the operator to converse `with said calling person, tosupervise on the connection and to cause the collection or refunding ofany coins subsequently deposited in payment for overtime periods ofconversation.

8. In a telephone system, a rst ofce, a coin box line terminatingtherein, a tandem oiiice, terminating offices, switching mechanism insaid oices, control means in said tandem office, an operators positionhaving cord circuits in said rst cnice, a trunk extending between saidfirst and said tandem oiiices having an appearance in the switchingmechanism of said rst office and a lamp, an answering jack and asplitting jack appearance at said operators position for each of aplurality of charge rates for calls from said line to desired linesterminating in said terminating offices, means operated upon the seizureof said trunk to prepare said control means for controlling thecompletion of the desired connection and for lighting the lamp at saidoperators position indicative of the charge rate for the desiredconnection, means operated in response to the connection 0f a cordcircuit of said position to the answering jack associated with thelighted lamp to enable the operator to request and to check the depositof a coin or coins in payment for the initial period of conversation,means responsive to the disconnection of said coi'd circuit from saidjack for signaling said control means to proceed with the control of thecompletion of the desired connection,v means operative a predeterminedperiod following the response of the called subscriber for causing thecollection of the deposited coin or coins and for flashing the lamppreviously lighted at the end of the initial period allowed forconversation, means responsive to the connection of a cord circuit tothe answering jack associ'ated with the ashing lamp to enable theoperator to request and to check the deposit of a coin or coins for anovertime period of conversation9 and means eiective upon the connectionof another cord circuit with the splitting jack associated with theflashing lamp to enable the operator to talk with either the callingperson or the called subscriber but to prevent the calling person andcalled subscriber from talking with each-other.

9. In a telephone system, a first office, a coin box line terminatingtherein, a tandem office, terminating offices, switching mechanism insaid offices, control means in said tandem oice, an operators positionhaving cord circuits in said first office, a trunk extending betweensaid rst and said tandem offices having an appearance in the switchingmechanism of said :("irst` oiiice and a lamp, answering jack andsplitting jack appearance at said operators position for each of aplurality of charge rates for calls from said line to desired linesterminating in said terminating oices, means operated upon the seizureof said trunk to prepare said control means for controlling thecompletion of the desired connection and for lighting the lamp at saidposition indicative of the charge rate for the desired connection, meansoperative following the connection of a cord circuit of said position tothe answering jack associated 'with the lighted lamp for enabling theoperator to request and to check the deposit of the required coin orcoins, and means responsive to the connection of another cord circuit tothe splitting jack associated with the lighted lamp in the event thecalling person does not respond and has left the station withoutrestoring the receiver to the switchhook for preparing the trunk andtandem oice apparatus for restoration to its normal condition upon thedisconnection of said cord circuits from said jacks. N

CHESTER E. BROOKS. ERLON W. IFLINT.

